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:-) (CVS 147)

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FossilOrigin-Name: e11f7527f9187e8902db84069baad0d3b7e17ad0
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drh
2000-09-29 13:30:53 +00:00
parent 6d31316cf3
commit e371033ddf
12 changed files with 342 additions and 39 deletions
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68
www/c_interface.tcl
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@ -1,7 +1,7 @@
#
# Run this Tcl script to generate the sqlite.html file.
#
set rcsid {$Id: c_interface.tcl,v 1.7 2000/08/22 13:40:20 drh Exp $}
set rcsid {$Id: c_interface.tcl,v 1.8 2000/09/29 13:30:55 drh Exp $}
puts {<html>
<head>
@ -22,8 +22,8 @@ programming interface.</p>
<h2>The API</h2>
<p>The interface to the SQLite library consists of six functions
(only three of which are required),
<p>The interface to the SQLite library consists of eight functions
(only the first three of which are required),
one opaque data structure, and some constants used as return
values from sqlite_exec():</p>
@ -42,6 +42,17 @@ int sqlite_exec(
char **errmsg
);
int sqlite_get_table(
sqlite*,
char *sql,
char ***result,
int *nrow,
int *ncolumn,
char **errmsg
);
void sqlite_free_table(char**);
int sqlite_complete(const char *sql);
void sqlite_busy_handler(sqlite*, int (*)(void*,const char*,int), void*);
@ -210,6 +221,57 @@ being queried.
</dl>
</blockquote>
<h2>Querying without using a callback function</h2>
<p>The <b>sqlite_get_table()</b> function is a wrapper around
<b>sqlite_exec()</b> that collects all the information from successive
callbacks and write it into memory obtained from malloc(). This
is a convenience function that allows the application to get the
entire result of a database query with a single function call.</p>
<p>The main result from <b>sqlite_get_table()</b> is an array of pointers
to strings. There is one element in this array for each column of
each row in the result. NULL results are represented by a NULL
pointer. In addition to the regular data, there is an added row at the
beginning of the array that contains the names of each column of the
result.</p>
<p>As an example, consider the following query:</p>
<blockquote>
SELECT employee_name, login, host FROM users WHERE logic LIKE 'd%';
</blockquote>
<p>This query will return the name, login and host computer name
for every employee whose login begins with the letter "d". If this
query is submitted to <b>sqlite_get_table()</b> the result might
look like this:</p>
<blockquote>
nrow = 2<br>
ncolumn = 3<br>
result[0] = "employee_name"<br>
result[1] = "login"<br>
result[2] = "host"<br>
result[3] = "dummy"<br>
result[4] = "No such user"<br>
result[5] = 0<br>
result[6] = "D. Richard Hipp"<br>
result[7] = "drh"<br>
result[8] = "zadok"
</blockquote>
<p>Notice that the "host" value for the "dummy" record is NULL so
the result[] array contains a NULL pointer at that slot.</p>
<p>Memory to hold the information returned by <b>sqlite_get_table()</b>
is obtained from malloc(). But the calling function should not try
to free this information directly. Instead, pass the complete table
to <b>sqlite_free_table()</b> when the table is no longer needed.</p>
<p>The <b>sqlite_get_table()</b> routine returns the same integer
result code as <b>sqlite_exec()</b>.</p>
<h2>Testing for a complete SQL statement</h2>
<p>The last interface routine to SQLite is a convenience function used